Cucumber (Cucumis sativus L.) is one of the most cultivated vegetable crops in plastic greenhouses in Brazil because of the short cycle and its high economic value in off-season harvests. To better understand this management technique the effect of different colored polyethylene soil covers was evaluated in relation to flowering and yield of the hybrid cucumber 'Yoshinari' grafted or not on the hybrid squash 'Ikky'. The polyethylene cover colors were black, white on black and green plus a control without cover. Covered but not grafted crops had a more uniform flowering distribution. The number of flowers was greater for the white/black grafted treatment. All the polyethylene covers favored flowering for the non grafted plants. Grafting reduced flowering for the black or green polyethylene covers treatments. The fruit set increased with the use of polyethylene cover but was not influenced by grafting. The uniform distribution of flowering remained during fruiting only for grafted plants and soil covered with black or green polyethylene. Both polyethylene cover and grafting favored early harvesting. The 'Yoshinari'/'Ikky' graft caused taller plants but fruit were thicker and smaller and did not meet the commercial standard. The best quality fruit and highest yields were obtained in the black and white/black treatments, without grafting.
Cucumis sativus; Cucurbita spp.; plastic greenhouse; rootstock